I've only ever been able to get Class 4 cards working with the sparkfun block. The Arduino breakout board from Intel works with Class 10 cards, though. Not sure if that is usable for your project or not.

g.gregory, thank you for the suggestions on the sparkfun thread, I did try them. The problem is that /dev/mmcblk1 and /dev/mmcblk1p1 do not exist. I do not know if they are dynamically created when the card is recognized of one needs to create them with mknod. With no /dev file, the mount command fails.

The output from dmesg is actually the error message in the the title of this thread:

mmc1: error -110 whilst initialising SD card

I have verified that this message appears each time a card is inserted.

I have ordered a class -4 card on the suggestion of Kevin above, but have not yet received it. The only other card that I have is a 64Gb class 10, but as I understood it 32 is the limit. I might just pop it in there to see what happens (not expecting it to work).